Light sources in conventional edge-lit light guide luminaires may produce visual hot spots of light, i.e., non-uniform brightness or glare across the light guide that is undesirable to a user. Typically, the hot spot effect may be suppressed by using diffusers and/or reflectors. However, while the diffusers and/or reflectors are capable of suppressing the hot spot effect to a certain degree, they are still not satisfactory because of light leakage around the perimeter of the diffusers and/or reflectors in conventional edge-lit light guide luminaires. Such light leakage from around the perimeter of the diffusers and/or reflectors may create an undesirable visual effect and further reduce the efficiency of the luminaire. Furthermore, conventional luminaires may not be configured for easy replacement of an already installed diffuser and/or reflector once the luminaire is installed and operational. Thus, there remains a need for an edge-lit light guide luminaire that can satisfactorily suppress the hot spot effect on the light guide, while enabling easy installation/replacement of a diffuser and/or reflector and preventing light leakage from the perimeter of the diffuser and/or reflector.